Alpha-olefins, especially those containing about 6 to about 20 carbon atoms, have been used as intermediates in the manufacture of detergents or other types of commercial products. Such alpha-olefins have also been used as comonomers, especially in linear low density polyethylene. Commercially produced alpha-olefins are typically made by oligomerizing ethylene. Longer chain alpha-olefins, such as vinyl-terminated polyethylenes are also known and can be useful as building blocks following functionalization or as macromonomers.
Allyl terminated low molecular weight solids and liquids of ethylene or propylene have also been produced, typically for use as branches in polymerization reactions. See, for example, Rulhoff, Sascha and Kaminsky, (“Synthesis and Characterization of Defined Branched Poly(propylene)s with Different Microstructures by Copolymerization of Propylene and Linear Ethylene Oligomers (Cn=26-28) with Metallocenes/MAO Catalysts,” Macromolecules, 16, 2006, pp. 1450-1460), and Kaneyoshi, Hiromu et al. (“Synthesis of Block and Graft Copolymers with Linear Polyethylene Segments by Combination of Degenerative Transfer Coordination Polymerization and Atom Transfer Radical Polymerization,” Macromolecules, 38, 2005, pp. 5425-5435).
Further, U.S. Pat. No. 4,814,540 discloses bis(pentamethyl cyclopentadienyl) hafnium dichloride, bis(pentamethyl cyclopentadienyl) zirconium dichloride and bis(tetramethyl n-butyl cyclopentadienyl) hafnium dichloride with methylalumoxane in toluene or hexane with or without hydrogen to make allylic vinyl terminated propylene homo-oligomers having a low degree of polymerization of 2-10. These oligomers do not have high Mns and do not have at least 93% allylic vinyl unsaturation. Likewise, these oligomers lack comonomer and are produced at low productivities with a large excess of alumoxane (molar ratio ≧600 Al/M; M=Zr, Hf). Additionally, no less than 60 wt % solvent (solvent+propylene basis) is present in all of the examples.
Teuben, et al. (J. Mol. Catal., 62, 1990, pp. 277-287) discloses the use of [Cp*2MMe(THT)]+[BPh4] (M=Zr and Hf; Cp*=pentamethylcyclopentadienyl; Me=methyl, Ph=phenyl; THT=tetrahydrothiophene), to make propylene oligomers. For M=Zr, a broad product distribution with oligomers up to C24 (number average molecular weight (Mn) of 336) was obtained at room temperature. Whereas, for M=Hf, only the dimer 4-methyl-1-pentene and the trimer 4,6-dimethyl-1-heptene were formed. The dominant termination mechanism appeared to be beta-methyl transfer from the growing chain back to the metal center, as was demonstrated by deuterium labeling studies.
X. Yang, et al. (Angew. Chem. Intl Ed. Engl., 31, 1992, pp. 1375) discloses amorphous, low molecular weight polypropylene made at low temperatures where the reactions showed low activity and product having 90% allylic vinyls, relative to all unsaturations, by 1H NMR. Thereafter, Resconi, et al. (J. Am. Chem. Soc., 114, 1992, pp. 1025-1032), discloses the use of bis(pentamethylcyclopentadienyl)zirconium and bis(pentamethylcyclopentadienyl)hafnium to polymerize propylene and obtained beta-methyl termination resulting in oligomers and low molecular weight polymers with “mainly allyl- and iso-butyl-terminated” chains. As is the case in U.S. Pat. No. 4,814,540, the oligomers produced do not have at least 93% allyl chain ends, an Mn of about 500 to about 20,000 g/mol (as measured by 1H NMR), and the catalyst has low productivity (1-12,620 g/mmol metallocene/hr; >3000 wppm Al in products).
Similarly, Small and Brookhart, (Macromolecules, 32, 1999, pp. 2322) disclose the use of a pyridylbisamido iron catalyst in a low temperature polymerization to produce low molecular weight amorphous propylene materials apparently having predominant or exclusive 2,1 chain growth, chain termination via beta-hydride elimination, and high amounts of vinyl end groups.
Weng et al. (Macromol Rapid Comm. 2000, 21, pp. 1103-1107) discloses materials with up to about 81% vinyl termination made using dimethylsilyl bis(2-methyl, 4-phenyl-indenyl) zirconium dichloride and methylalumoxane in toluene at about 120° C. The materials have a Mn of about 12,300 (measured with 1H NMR) and a melting point of about 143° C.
Markel et al. (Macromolecules, 33, 2000, pp. 8541-8548) discloses comb branch-block polyethylene made with Cp2ZrCl2 and (C5Me4SiMe2NC12H23)TiCl2, activated with methyl alumoxane.
Moscardi, et al. (Organometallics, 20, 2001, pp. 1918) discloses the use of rac-dimethylsilylmethylenebis(3-t-butyl indenyl)zirconium dichloride with methylalumoxane in batch polymerizations of propylene to produce materials where “ . . . allyl end group always prevails over any other end groups, at any [propene].” In these reactions, morphology control was limited and approximately 60% of the chain ends are allylic.
Coates, et al. (Macromolecules, 38, 2005, pp. 6259) discloses preparation of low molecular weight syndiotactic polypropylene ([rrrr]=0.46-0.93) with about 100% allyl end groups using bis(phenoxyimine)titanium dichloride ((PHI)2TiCl2) activated with modified methyl alumoxane (MMAO; Al/Ti molar ratio=200) in batch polymerizations run between −20° C. and +20° C. for four hours. For these polymerizations, propylene was dissolved in toluene to create a 1.65 M toluene solution. Catalyst productivity was very low (0.95 to 1.14 g/mmol Ti/hr).
JP 2005-336092 A2 discloses the manufacture of vinyl-terminated propylene polymers using materials such as H2SO4 treated montmorillonite, triethylaluminum, triisopropyl aluminum, where the liquid propylene is fed into a catalyst slurry in toluene. This process produces substantially isotactic macromonomers that do not have a significant amount of amorphous material.
U.S. Pat. No. 6,897,261 discloses olefin graft copolymers obtained by copolymerizing an atactic branched macromonomer, wherein the macromonomer is derived from monomers selected from the group consisting of (1) propylene and (2) the combination of propylene and at least one selected from ethylene, alpha-olefins having from 4 to 20 carbon atoms, cyclic olefins and styrenes, and of which the propylene content falls between 0.1 mol % and 100 mol %, and which macromonomer satisfies the following (a) and (b): (a) its weight-average molecular weight (Mw) measured through gel permeation chromatography (GPC) falls between 400 and 200000; (b) its vinyl content is at least 70 mol % of all the unsaturated groups in the macromonomer, wherein the macromonomer satisfies each of the following (i), (ii), and (iii): (i) the ratio of the temperature dependency (E2) of the macromonomer solution viscosity to the temperature dependency (E1) of the solution viscosity of the linear polymer which has the same type of monomer, the same chemical composition and the same intrinsic viscosity as those of the macromonomer, E2/E1, satisfies the following relationship: 1.0<E2/E1<2.5.
Rose, et al. (Macromolecules, 41, 2008, pp. 559-567) discloses poly(ethylene-co-propylene) macromonomers not having significant amounts of iso-butyl chain ends. Those were made with bis(phenoxyimine) titanium dichloride ((PHI)2TiCl2) activated with modified methylalumoxane (MMAO; Al/Ti molar ratio range 150 to 292) in semi-batch polymerizations (30 psi propylene added to toluene at 0° C. for 30 min, followed by ethylene gas flow at 32 psi of over-pressure at about 0° C. for polymerization times of 2.3 to 4 hours to produce E-P copolymer having an Mn of about 4,800 to 23,300. In four reported copolymerizations, allylic chain ends decreased with increasing ethylene incorporation roughly according to the equation:
% allylic chain ends (of total unsaturations)=−0.95(mol % ethylene incorporated)+100. For example, 65% allyl (compared to total unsaturation) was reported for E-P copolymer containing 29 mol % ethylene. This is the highest allyl population achieved. For 64 mol % incorporated ethylene, only 42% of the unsaturations are allylic. Productivity of these polymerizations ranged from 0.78×102 g/mmol Ti/hr to 4.62×102 g/mmol Ti/hr.
Prior to this work, Zhu, et al. (Macromolecules, 35, 2002, pp. 10062-10070 and Macromolecules Rap. Commun., 24, 2003, pp. 311-315) reported only low (˜38%) vinyl terminated ethylene-propylene copolymer made with the constrained geometry metallocene catalyst [C5Me4(SiMe2N-tert-butyl)TiMe2 activated with B(C6F5)3 and MMAO.
Janiak and Blank summarize a variety of work related to oligomerization of olefins (Macromol. Symp., 236, 2006, pp. 14-22).
U.S. Pat. No. 6,225,432 discloses branched polypropylene compositions which have improved melt strength and good processability. The branched polypropylene compositions have a polydispersity of less than 4.0 and a melt point greater than 90° C. The weight average branching index g of the polypropylene compositions is less than 0.95.
However, processes to make branched polyolefins having high amounts of allyl terminations on a commercial scale are not known. Accordingly, there is a need for new processes that produce allyl terminated branched polyolefins that have allyl termination present in high amounts (50% or more), particularly in high yields and with a wide range of molecular weights, that can be made at commercial rates (5,000 g/mmol/hr productivity or more). There is further a need for branched polyolefin reactive materials having high amounts of allyl termination which can be functionalized and used in additive applications or as blending components.